Using a Global Positioning System (GPS)
- GPS is a navigation system based on a network of 24 satellites. Users with a GPS unit can determine their exact location (latitude and longitude) in any weather conditions, all over the world, 24 hours a day.
- GPS receivers compare the time a signal was transmitted by a satellite with the time it was received. The time difference lets the GPS receiver calculate its distance from the satellite. By calculating its distance from several satellites, the receiver can determine and display the user’s location on the GPS unit.
- GPS units also can calculate information such as bearing, trip distance, distance to destination, and sunrise and sunset times.
- GPS receivers are accurate to within 15 meters (49 feet) on average. Certain atmospheric factors and other sources of error can affect the accuracy. Accuracy can be improved with a Differential GPS (DGPS) or WAAS (Wide Area Augmentation System).